This invention relates to web unit handling method and apparatus and, more particularly, to a method and apparatus which presents web units in convenient substacks for rapid and reliable accumulation into larger stacks.
The invention finds advantageous application to the handling of folded web units such as tissues and paper napkins and thus will be discussed generally in that context although many other types of web units, folded or unfolded, can be handled advantageously through the practice of the invention. For example, the invention finds application in the production of separate sub-stacks of flat sheets, of longitudinally but not transversely folded sheets, of flat sheets not longitudinally folded but single transverse folded (here the single fold does not have to define two equal panels), of longitudinally and transversely folded web segments--like a napkin or a multiple longitudinal fold and a single transverse fold like a hanky or non-longitudinally folded product which is double transverse folded, and of longitudinally folded and double transverse folded product--like a dinner size double transverse folded napkin.
A number of drawbacks attended the previous production of paper napkins. Foremost among these was a speed limitation of the order of 600-750 napkins per minute, per lane, this stemming from the arrangement of the folding and stacking mechanisms. Widening the machine was unattractive because of the substantially increased expense and difficulties of operation.
These difficulties and limitations have been avoided through the practice of the invention which involves separately advancing a plurality of web units along the same plurality of delivery paths, the delivery paths being aligned along a linear collection path. Thereafter, the web units are transferred into the collection path and advanced thereon in synchronism with other web units being transferred to the collection path to deliver a series of substacks which are then accumulated into the desired stack or "count".
Other objects and advantages of the invention can be seen in the details of the ensuing detailed description.